


The Book of Natsu

by Akiko_Natsuko



Series: Gratsu [42]
Category: Fairy Tail
Genre: Alternate Universe - Canon Divergence, Forgiveness, Friendship/Love, Grief/Mourning, Heavy Angst, Hope, Hopeful Ending, Love, M/M, Meaning of Life, Near Death, Promises, Protectiveness, Sacrifice, Secret Identity, Serious Injuries, Trust, life - Freeform
Language: English
Status: In-Progress
Published: 2019-02-05
Updated: 2019-02-05
Packaged: 2019-10-22 14:02:19
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,665
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17664011
Author URL: https://archiveofourown.org/users/Akiko_Natsuko/pseuds/Akiko_Natsuko
Summary: The world was burning around him, dark magic lashing against his skin, and all he could do was wrap himself around the book that he had hated for so long. The book that now offered him the only hope he had of getting Natsu back.“I swear it, I’ll protect you… until the very end.”





	The Book of Natsu

**Author's Note:**

  * For [mdelpin](https://archiveofourown.org/users/mdelpin/gifts).



> Based on this [wonderful artwork](https://x-thekid.tumblr.com/post/182480010614/i-swear-it-ill-protect-you-until-the-very) by x-thekid on tumblr.

_“Life will break you. Nobody can protect you from that, and living alone won't either, for solitude will also break you with its yearning. You have to love. You have to feel. It is the reason you are here on earth. You are here to risk your heart. You are here to be swallowed up. And when it happens that you are broken, or betrayed, or left, or hurt, or death brushes near, let yourself sit by an apple tree and listen to the apples falling all around you in heaps, wasting their sweetness. Tell yourself you tasted as many as you could.”_  
― Louise Erdrich, The Painted Drum

 

     Gray knew that he was going to get an earful from Erza later, and there was a prickle of fear at that knowledge because even now he had to admit that she could be terrifying. _But this is Natsu…_ he had meant it when he said that he did have faith in the Dragon-slayer, and he did, more than he’d ever had in anyone else, which was why he was worried. Because he knew how far Natsu was willing to go to protect the guild, to protect him. _And how far will he have to go this time?_ It was that thought that terrified him, and as much as he trusted Happy to take care of the idiot, he knew that there was only so much the pair of them could do. And that even if Natsu succeeded, there was still an army around them, and he wasn’t sure how much faith he had in the idea of cutting the head off the snake. Which was why he was here, staggering as Mest deposited them a short distance from where they had last seen Natsu’s blip on the map.

      It didn’t take long to locate the wayward Dragon-slayer, as the air around them was an inferno that had them both recoiling, and Gray was already tugging at his coat, as there was an explosion somewhere up ahead, followed by a roar that seemed to reverberate through the very earth and his lips twitched. _Natsu._

“Gray…”

“Head back, I’ll handle things here,” Gray cut across him, glancing at the other man and seeing the fear in his eyes, not that he could blame him because now he was focusing, he could feel the magic in the air. Natsu’s was familiar, although there was something different about it, something that had the hairs on his arms standing on air. _Natsu, what the hell do you have up your sleeve?_ A small part of him had thought that Natsu was bluffing when he’d claimed to have a secret weapon, wondering if the Dragon-slayer had just been trying to give them something to believe in. But now he wasn’t sure, because this…the heat, the strength of the magic, it was more than he had ever felt from Natsu before, and it scared him. Although not as much as the other magic he could feel tingling against his skin, magic that he hadn’t felt since Tartaros, and that he had hoped that he would never feel again.

_Zeref…_

     Mest hesitated for a moment, clearly reluctant to just leave him out here, but then he sighed and glanced towards where another explosion had just rent the air. “Be careful,” he warned, and then he was gone, leaving Gray behind. _I’ll try,_ he thought, already knowing that it was a promise that he was going to break because this was Natsu….

_Flamebrain, why did you go alone…?_

    That was the one thing he didn’t understand about any of this, because Natsu more than any of them, had always been the one to believe in fighting together. He drew strength from them, just as they found strength in his fire, his resolve, so for him to go alone. _Does he not expect to come back from this?_ He stumbled at that thought, unable to imagine it, and yet… cursing he broke into a run, ignoring the part of his mind that was screaming at him to get as far away from the magic and heat ahead of him as possible.

     The land around him had been deformed, twisted by an immense heat, and the ground was still warm, burning through his shoes to the point where he was forced to summon a fine layer of ice against his skin. _Natsu._ He glanced up as a plume of fire shot skywards, and oddly enough it was reassuring to see it, to know that Natsu was still fighting, and still going overboard. And he wasn’t alone, because in a brief break in the plumes of smoke he glimpsed the small figure of Happy soaring through the sky, no doubt watching and waiting for when he was needed. _And I’m here Flamebrain, you don’t have to do this alone,_ he added, as he scrambled up a jagged pile of rocks that were veined with red from the Dragon-slayer’s flames.

      He had just made it to the summit when there was an explosion, the kind of blast that only two powerful magics could create, and he had to dig his fingers into the rock and hold on as the force of it threatened to send him flying back over the edge. It felt like he was roasted alive, his eyes watering as he took in the flames that filled the world ahead of him, noting the darker colour, the wildness that he hadn’t seen since the day he had finally seen Igneel and watched him fight. _Is this what you were hiding?_ His arm burned, the magic he had inherited flaring in sympathy for Natsu, and he let the dark marks start seeping over his skin as the flames, and smoke slowly began to clear away, and his heart was in his mouth until he finally set eyes on the Dragon-slayer.

    Natsu looked worse for wear, but he was standing firm. However, Gray’s breath caught as he glimpsed the deep gash marring the Dragon-slayer’s cheek, fingers itching to reach out, but before he could reveal himself there was movement beyond Natsu, and he felt a familiar tremor wrack him as Zeref stepped into view. Natsu, on the other hand, wasn’t flinching, flames gathering around his arm as he readied himself to attack again, and this time Gray glimpsed the dragon marking against tan skin, mouth dropping open. _He wasn’t lying…_ The markings on his own arm were spreading, and now that he wasn’t currently in danger of being flung backwards, he allowed his hands to curl into fists, his magic beginning to stir. However, before he could give in to the temptation to move to Natsu’s side and join the fight, Zeref spoke, stepping towards Natsu.

“But there’s something I’d like to tell you while I’m still alive,” Zeref’s voice was mellow, nothing like the intimidating tone in Gray’s memories, and there was something akin to…tenderness in his expression as he studied Natsu, and Gray found himself bristling, more unnerved by that than he would’ve been by an attack. “My name is Zeref Dragneel.” _Wait? What?_ Gray’s mind was racing, but his gaze was fixated on Natsu’s face, and he could see the confusion beneath the anger. _He didn’t know?_ Natsu had never been good at hiding his emotions, and Gray was better than most at reading him, and there was no trace of a lie in the set expression…and no feigning the shock that followed the next five words. “And I am your brother.”

_Brother?_

_Natsu has a brother…Zeref is his brother?_ Gray’s mind was stuck between those thoughts, bouncing between too fast to grasp hold on either one, something dark and ugly twisting in his chest as he stared at Natsu who had gone rigid. He knew better than anyone how important family was to Natsu. Hell, he had spent years searching for a Dragon, enduring their doubts and occasional ridicule, persevering through false leads and disappointments, only for it all to be snatched away. It had been Natsu who had put what they were all feeling into words, verbalising the fact that they were going to be fighting for their family, regardless of what they were going to be facing. Natsu who had rarely ventured from his side since Fairy Tail had reformed, desperately clinging to what they had, and now…

_Now what?_

    Zeref was their enemy, and there was nothing about the scene in front of his eyes that suggested that had changed, even with the odd fondness that had seeped into the man’s eyes as he stared at Natsu. But, could they ask Natsu to fight him if he was telling the truth? Could Natsu fight him? For once Gray wasn’t sure, the uncertainty biting deeper than the terror that had gripped him when he’d first realised that Natsu had gone charging off to meet Zeref alone. “It was 400 years ago; both our parents were killed by Dragon Embers…” Gray blinked, realising that Zeref was still speaking, although the words were making no sense to him, although his heart ached at the words. That was a loss he wouldn’t wish on his worst enemy and Natsu…Natsu was still reeling from losing Igneel even if he hid it well most of the time, and for the first time, he could see a hint of uncertainty in the Dragon-slayer’s eyes. “And you too in fact.” Natsu and Gray stiffened in unison at that, and it took everything Gray had to hold his position, even as the dark feeling that had twisted in his chest, swelled and deepened, something stirring in the back of his mind. “I did everything in my power to bring you back, and I created something called the Etherious in the process.”

_Etherious_

_E…._

_No…Nonono,_ Gray was shaking his head, trying desperately to stop the thought from solidifying in the back of his mind. _It can’t be him…_

“W-What are you talking about?” Natsu’s voice cracked and broke, uncertainty and fear bleeding through, but this time as much as Gray ached to go and help him, he couldn’t move. Sensing that they both needed to hear this, even as dread pooled in the pit of his stomach, the promise he had made to Silver screaming in the back of his mind. _Please, don’t let it be him._

“And that was you, Natsu…” Zeref was smiling now, sickening Gray, but not as much as the words that followed. “Etherious Natsu Dragneel.” _No,_ the denial was weak even in the privacy of his own mind, the darkness screaming to life, his magic seeping out and freezing the rocks beneath his hands as Zeref said the one name that had driven him forward for the past year.  “E.N.D.”

_E.N.D._

_Etherious Natsu Dragneel._

_Natsu….?_

“First, I’m your brother, and now I’m END?” Natsu roared, but it lacked the ferocity and certainty of his usual shouts, and Gray could see the tremors that he was trying to hide, even as his flames sprang to new heights around his hands. “Ye…Yeah…” Gray closed his eyes, hearing the hurt and pain… the anguished longing that the Dragon-slayer would never admit to feeling, his heart going out to Natsu, and his eyes flew open in alarm as the heat in the air around them reached new heights. “I’ve had enough of that.”

“N-Natsu! Don’t listen to him!” Happy was screaming, having drifted lower and Gray hated himself for not being able to add his voice to that shout. _This is Natsu…_ It was Natsu, the same idiot who had squared off against Deliora for Gray’s sake back before they were anything more than reluctant teammates. The same idiot who had rushed out here to try and protect their family. The Natsu who was stepping forward, still ready to fight, even as he wavered in the grip of pain and uncertainty. _Its Natsu, so why isn’t that enough…?_

“I heard that Igneel couldn’t destroy END,” Natsu gave no sign that he had heard his best friend, taking a step towards Zeref, his expression twisted with pain and rage. “If I were END then he could’ve destroyed me easily!” There it was – the same ache, the same grief that slipped through late at night when Natsu roused them both with nightmares, or when they had mentioned Tartaros or Acnologia, and Gray took a deep breath.

_This is Natsu…_

“He couldn’t because he loved you. He could’ve killed you, but he didn’t.”

_Because he loved you…_

_Because I love you…_

    In that split second Gray knew that he was going to break his promise to Silver, and there was a stinging in his eyes as his hands unclenched, the ice fading from the rocks around him. _This is Natsu, no matter who else or what else he might be, I can’t forget that._

_I won’t forget that._

“END is what created those Tartaros Monsters!!” Natsu control was wavering, desperation bleeding through into the words. “Not me, I’m human!!” Gray could hear the doubt, the terror that Zeref might actually be telling the truth, and suddenly all his proclamations about hating E.N.D. and swearing to destroy the demon came rushing back to him, nausea rising. _Why did I say that to him?_ Rationally he knew that he could not have known that this was coming. The thought had never even entered his mind, even with the interest that Zeref seemed to have taken in the Dragon-slayer every time they had encountered one another, and yet his heart ached, knowing without a doubt that those words would be echoing around in Natsu’s mind right now.

“Mard Geer made Tartaros. He just happened to pick this up and made it sound as if it made him make all those monsters,” Zeref corrected, and magic shifted in the air in front of him, and Gray’s breath caught in his chest as the book that he had dreamed about and focused on for a year shimmered into view. He had hated that book, but now he feared it, a tremor wracking his body. _That book is part of Natsu…and I wanted to destroy it._ “But, maybe in that sense, it would mean that you made those monsters.”  Gray gasped at those words, fury breaking through the shock even before he saw the way that Natsu flinched before the Dragon-slayer shook his head, screaming his denial.

“That’s why I’m telling you, I’M NOT E.N.D!” 

_Natsu…_

     Zeref was smiling, as though amused by the desperate defiance, even as he casually tossed the Book of E.N.D. towards the ground. Gray hated the fact that even just half an hour ago he would have been lunging at that opportunity, only to freeze in horror as there was a flare of magic, a shard of darkness that pierced through the book. _No…_ He was moving, scrambling into view even though neither seemed to notice him, only to freeze in place as Natsu screamed, the flames around him dying as the Dragon-slayer grabbed his side desperately. Blood was seeping between his fingers, and there was a sinking feeling in Gray’s heart as he realised that this newest wound matched the hole that he had just watched be blasted through the book.

 “See you never one to listen…” Zeref commented, and the Ice Mage bristled, hating to hear the words that he had turned in Natsu’s direction more time than he could count. “You didn’t even want to learn how to read or write. That’s why I went to a friend of mine to talk about it. Igneel…”

“Igneel, your friend?” Natsu was distracted, still clutching his side, but his flames were beginning to burn again as he focused on Zeref with the single-minded focus on a grieving child who had just been told he didn’t know everything about his parent.

     Gray’s focus was elsewhere, his mind racing as he stared at the Book that was still lying on the ground between the two…brothers. _Natsu is connected to the book…._ A small part of him had been wondering if would be possible to destroy the book, to destroy the demon, and leave Natsu – his Natsu untouched, but that single display had just destroyed that hope. If hurting the book, would hurt Natsu then there was no way he could even take the chance of it working in the end. He couldn’t hurt Natsu, not more than he already had been hurt by these revelations, or by the words that Gray had so naively thrown at him.

_So, how are we supposed to win?_

      They needed to end the war before they lost everything, and yet the only way for that to happen was to win, and for that, they needed to fight. But, how could they? How could they fight when Natsu’s life might end up on the line? How could they ask the Dragon-slayer who had already lost so much, to destroy a family he hadn’t even known about until just now? Sure, they all knew that the guild came first. Laxus had proven it when he had faced down his father, as had Lucy when she had gone home after the incident with Phantom Lord, but…

_This is different…_

“…All I needed was for you to become stronger. Strong enough to kill me, was what I had hoped you would become.” Gray’s head shot up as the conversation raging in front of him broke through his thoughts, horror gripping him. _You want him to kill you?_ It was only then that he realised that some tiny part of him had been fooled by the tenderness in that gaze, wondering if there could be more to the newly revealed relationship than what he had been able to see in his anger. Now though, rage bubbled up as he realised that Zeref didn’t see Natsu as his brother, but as a tool, a weapon forged for his own purpose, rather than a living, breathing individual with dreams and hopes and a purpose all of his own.

“I’ve been waiting for you all this time,” Zeref whispered, but Gray felt no sympathy for the longing in those quiet words, his gaze locked on Natsu once more, realising that the Dragon-slayer was rigid. The emotions that had been so clearly written across his face not long before, now hidden beneath a blank mask, although his eyes were blazing. _Natsu, what are you thinking?_ He didn’t like this side of the Dragon-slayer, fear gnawing at him, as for the first time he realised that he didn’t know how he was going to react, or what he was going to choose.  “But 400 years was a long time, and a lot has happened since then…” That was something that was going to take a long time to wrap his head around, but that could wait. Gray could live with that, as long as they both survived long enough to work through it together. “I’ve seen so many civilisations come to an end, I’ve begun to lose my feelings towards life and death. I met Mavis, and lost her…”

“SHUT UP!” Natsu erupted, the flames that had dimmed under his uncertainty, roaring to life once more, and with the few steps, closer that Gray had taken the heat was blistering. _Natsu…_ he was already moving, ignoring the voice that sounded a little too like Erza, that was telling him this wasn’t something he wanted to get in the middle of.

“I…”

“There’s no way I’m believing anything you say!!”

“You are a demon of the book of Zeref,” Zeref was unfazed by the Dragon-slayer’s – and Gray refused to think of him as anything else, no matter what the man called him – anger, spreading his arms wide. “If I die, you will die too.” To Gray, it felt like he had just been punched in the chest, even though it was just confirming what he had already suspected, his heart aching as he turned worried eyes back to the Dragon-slayer. Who wasn’t stopping, or even faltering at the news… _did he work it out already? Or does he just not care?_ Gray wasn’t sure what he wanted the answer to be, and it didn’t really matter as Natsu lunged forward, and the Ice Mage realised that he still intended to fight Zeref.

To end it all, no matter what the cost.

“Well, what about it?!!” Natsu was screaming as he charged, flames engulfing him, and for a moment all Gray could see was himself standing in front of Deliora, Iced Shell forming around him, ready to sacrifice himself.

“Natsu!!” He shouted, slamming his hands together and sending his ice roaring towards the two mages, desperately trying to block Natsu’s path. _You idiot, you’re the one that stopped me back then. So, now it’s my turn to return the favour._ Natsu had flinched at his voice, glancing towards him although he hadn’t slowed, and Gray was taken aback by the fear in the olive eyes that met his gaze all too fleetingly.

_He’s afraid…of me…_

“I’m not hesitating!! I’ve made up my mind!! I came all this way to defeat you!!” Natsu blasted through the ice that had only just reached him, Gray’s hesitation having bled through to his magic, and he watched helplessly as the Dragon-slayer barrelled into Zeref, the resulting blast enough to send him stumbling back.

“This is your last chance to stop me,” Zeref was the first to recover, standing tall amongst the devastation, a smile curving his lips and, at that moment, Gray had never hated anyone as much as he did the other man.

“NATSU STOP!” He shouted again, vaguely aware of Happy’s voice joining his as the Exceed swooped down towards them, and the Ice Mage tried to bury the flicker of hurt when Natsu glanced at the cat rather than him.

“I can’t….” _I won’t,_ Gray heard the defiance, and he closed his eyes as understanding dawned on him, as though back to the fear he had seen. Natsu had remembered his promise about E.N.D, the words he had so carelessly spoken, and had feared what Gray was going to do now that he knew the truth. No. That glance had said that he thought he knew exactly what Gray was going to do, and Gray swallowed as it hit home that Natsu had honestly thought he was going to keep that promise, and that he wasn’t stopping, he wasn’t going to let Zeref’s words stop him to spare Gray from making that decision. He was trying to protect Gray when he was the one reeling and hurting from the revelations here.

    Still, it was a thought that gave him pause, a foul taste in his mouth as he questioned himself. _Would I? Would I have really fought Natsu if I hadn’t found out like this? Could I have kept my promise, even if it was Natsu standing in front of me?_ He desperately wanted to believe that the answer was ‘no’, that the memories, the feelings would’ve have been enough to curb his anger and make him think about what he was going to do, but he wasn’t sure, and that doubt made him falter. A hesitation that cost him, because Natsu hadn’t hesitated.

The resulting eruption of magic sent him flying backwards, and he was vaguely aware of Happy’s voice raised in alarm as he was also flung away from the scene. His unexpected flight was cut short by the side of the trough that Natsu’s magic must’ve created earlier, pain radiating through his back from the impact, but it was swiftly forgotten as he frantically sought out Natsu. The space where Natsu and Zeref had been stood was a burning ruin, smoke obscuring his view, although what little he could see showed veins of fire running through the new crater that marked the spot.

    Then he heard coughing, hope fluttering to life in his chest as through the smoke he caught a glimpse of Natsu’s scarf flapping in the air as the Dragon-slayer came into view. The Dragon-slayer was wavering, the mark having disappeared from his arm and as Gray watched he slumped to one knee, his entire body shaking. _Natsu._ Shaking off his pain he stumbled upright and began to move forward, ignoring the burning against his feet, distantly realising that he had shed his coat and shirt as well at some point, however, he was barely halfway to the Dragon-slayer when the voice he had been hoping to never hear again rang out.

“What a disappointment.” There was a flare of magic, and the smoke cleared enough to reveal Zeref standing tall amongst the burning devastation. He wasn’t untouched, but it was clear that he was far from ready to fall, his magical presence seeming to swell around them. “I had hoped for more from you, Natsu.”

“Go to hell…” Natsu growled breathlessly, trying to struggle back to his feet, but he clearly lacked the strength, and he ended up slumped on both knees. However, he still managed to lift his head, baring his teeth in defiance as Zeref moved towards him, unwavering in his defiance even as Zeref lifted his hand in a motion that they both recognised from a year ago.

“Natsu!” Gray roared, terror gripping him as he charged forward, the memory of a different fight, and a different demon playing through his mind. _Mard Greer, defeated and desperate, the light that had glistened in his eyes when Zeref had appeared fading to despair as he realised what was going to happen._ The marks were spreading up his arms and side, ice paving his way through the burning landscape, but he knew that it wasn’t going to be enough. Even before he felt Zeref’s magic surging before the dark cloud engulfed Natsu and the book had risen, shimmering in the air between them, undamaged apart from the hole that Zeref had blasted through it not long before. “NATSU! STOP!”

    He didn’t expect his pleas to be answered, but it didn’t stop him from trying. The Dragon-slayer’s name a mantra driving him forward, but he knew that it was too late, even before he heard Natsu’s scream of pain, the dark cloud pulsating with light. When it cleared a second later, there was no sign of Natsu, the book of E.N.D covered with fiery veins as it floated in mid-air, and for a moment Gray’s mind went white. _Natsu…_

“Natsu!” He was still barrelling forward, the world coming back into focus as he realised that Zeref was moving again, all traces of the tenderness he had glimpsed lost, the dark eyes burning crimson as he stared at the book and smiled. It was a smile that promised death and destruction, and Gray howled as he realised what he was intended, his magic bursting out of him, the world narrowing to the book ahead of him. He didn’t care that he could be rushing to his death, that it might be too late, all he could see was the book that was his last lifeline to the Dragon-slayer he loved.

     Then he was lunging forward and snatching the book out of the air, glimpsing the fury on Zeref’s face from the corner of his eye, but refusing to falter, even as he felt the man’s magic flaring out towards him. It burned against his trembling fingers, but he didn’t release his hold on it, and he pulled it close as he hit the ground hard and rolled, narrowly avoiding the dark magic that blasted the ground just behind him. The world was burning around him, dark magic lashing against his skin, and all he could do was wrap himself around the book that he had hated for so long. The book that now offered him the only hope he had of getting Natsu back.

“I swear it, I’ll protect you… until the very end."

 


End file.
